Hearing aid



April 2, 1957 D. H. ROWLAND HEARING AID Filed F'eb. 27, 1953 INVENToR,

United States PatentO HEARING AID Douglas 1H. Rowland, Oklahoma City,lda.

Application February 27, 1.953, Serial No. 339,325

y Claims. (Cl.'17P9-107) The present invention relates to apparatus 'foramplifying sound, and more particularly to sound amplifying mechanism ofthe type commonly called a hearing aid, in contradistinction to publicaddress systems, radio receiving sets,.and the like.

V"Ille principal object lof the invention .is to provide a hearing aidwhich, a person having faulty yhearing faculties may wear in -his ear,to at least partially overcome his afic'tion.

A further important object is to provide a single-unit hearing aid whichrequires no externally exposed wires, and which eliminates the necessityof carrying any battery package or receiving set.

All elements, which go to make up the apparatus of thepresent-invention, are contained in an ear-piece.

,Another object is to lprovide an apparatus of this class which is nolarger than-the ear-piece which `forms a portion of most conventionalhearing aids.

Other objects will A'be 'apparent lfrom the 4following description whentaken in conjunction with the accompanying single sheet of drawings,wherein:

Figure l is an elevational view of an ear-,piece mounted in an auralorifice, the dotted 4lines showing a human ear within the oriiice ofwhich the ear-'piece is mounted;

Figure 2 is a perspective view of the ear-piece, per se;

'Figure 3 .is a sectional view taken :substantially along 'the line 3-3of Fig. l, said ear-piece containing one embodiment of the invention;

Figure 4 ris a `sectional view through an ear-piece containing aslightly different embodiment of the invention; and,

Figure 5 is a schematic view of an electric circuit made in accordancewith the invention.

Like characters yof reference designate like parts in those gures of thedrawings in which they occur.

In the drawings:

Referring more particularly to Fig. 5 of the drawings, wherein thevarious elements which go to make up the device are showndiagrammatically, the reference numeral 1 indicates, as a whole, acrystal pick-up transmitter or microphone which is conventional inoperating principle. One terminal of the transmitter 1 is connected by awire 2 to one pole of a seat 3 of electrical energy, and a wire 4 leadsfrom the other pole of said seat to one terminal of a receiver 5. Thereceiver 5 is conventional and may well be any one of the small types incommon use in electronic hearing aids.

The other terminal of the receiver 5 is connected by a wire 6 to a novelsound amplifying unit 7, more fully described hereinbelow which isconnected to the transmitter 1 by a wire S. A conductor 9 leads to agrid connection of the amplifier 7 from the wire 4.

It was said above that the transmitter 1 and the receiver 5 both operateon conventional principles, but this does not mean that they areentirely conventional in construction, since in order for them tofunction in a desired manner, they must be made very small, as will morefully appear hereinbelow. The `sound amplifying unit 7 op- 2,787,579'Patented pr. 2, 1957 rice erates upon a conventional principle, but ismuch smaller than most conventional amplifiers.

The amplifier 7 is shown diagrammatically in the drawings to be agermanium transistor. This is important because in order to conservespace, a germanium transistor can be made very small and yet it willperform the functions of 'an electronic vacuum tube many times its size.Furthermore it consumes only a small fraction of the electrical energyused by an electronic tube designed for the same purpose and does notneedany warm-up time before 'it starts operating. rIlhe sea't 3 ofelectrical energy may be in the form of a dry-cell battery as shown inFig. 5, or it may well be a bi-metal thermal generator energized by theapplication of heat, as illustrated in Fig. 3.

In accordance with the present invention, the above described apparatusis adapted for use as a hearing aid Vfor one individual person, and asis more fully described hereinbelow, the apparatus is so 'arranged thatit may all be embodied in a single plug or ear-piece.

Referring now moreparticularly to Fig. 4 of the drawings, the referencenumeral 2t) indicates, as a whole, a preformed body of some suitablenon-conductive material, for instance one of the plastics, 4eithermineral or vegetable. The coniiguration of the body 20 is such that itcontiguously contacts the concha of the ear and has an inwardlyextending stud portion 21 formed to lit snugly within the externalauditory canal of a persons ear, said stud 21 having an inner endsurface 22 and an outer end surface 23. The outer end 23 of the stud 2lis surrounded by an integral ange portion 24 which has a central cavity25 which immediately surrounds said outer end 23. The body 20 'furtherincludes a llaterally upwardly projecting portion '26 which "issubstantially cylindrical exteriorly, and the outermost end of which isprovided with a cavity having-tapered female threads 27.

A dry-cell battery elementZS having a threaded endportion S29 lengaged'with the threads V27 and an exterior configuration to conform with theshape of 'the hollow of the fossa'of the anthelix portion of an ear. Thebattery elementZS :has al carbon core 30 which is the positive plateextending from the threaded end 29 to a point adjacent the opposite orupper end of the battery 28 as at 32, and is constructed in theconventional manner of dry-cell battery manufacture using a conventionalelectrolyte, except for the exterior conguration and having a metalshell, not shown, for the negative plate. The ends ofthe wires 2 and 4are positioned to contact the positive and negative plate, respectively,of the battery 28.

In constructing the body 20, the sound receiving apparatus 1, is locatedas shown in Fig. 4, embedded within the outer end 23 of the Vstud 21 andat the foot of the cavity 25. The amplifying unit 7 is embedded in thecentral portion of the stud 21, land the receiver 5 is embedded in thestud 21 adjacent its inner end surface 22. The wires or `cculductors 2,4, 6, 8 and 9 are all embedded in the stud 21 with the exception ofslight portions of the wires 3 and 4 which terminate at the foot of thecavity in the laterally projecting portion 26.

ln Figs. 2 and 3 of the drawings, there is shown an embodiment of theinvention wherein the battery is supplanted by a bi-metal thermalgenerator. In this latter embodiment, the body 1 and the lateralextension are formed integrally, there being a lateral extension portion4@ in flieu of the battery 28 of Fig. 4. Otherwise, the body of Fig. 3is quite similar in configuration and construction to the body shown inFig. 4.

The bi-metal thermal generator of the present embodiment is made in theform of a two-sheet jacket which contiguously covers all exteriorsurfaces of the body 20, including all of the stud 21 except itsinnermost end 22, and al1 of the lateral extension 40. The flangeportion 24 of the body and the bottom of the cavity 2S are left uuncovered by the jacket. The jacket is composed of two metal sheets, aninner sheet 41 and an outer sheet 42. The wire 2 is connected to theinner sheet 41, and the wire 4 is connected to the outer sheet 42 asshown in Fig. 3.

Operation 0f the device is thought to be obvious. Sound received by thetransmitter 1 is amplified by the element 7, and is then discharged bythe receiver 5 in the proximity of the wearers ear drum, not shown. Ofcourse, more than one of the amplifying units may be interposed withinthe circuit, if desired.

Heat from the wearers body actuates the thermal generator.

Obviously the invention is susceptible to some change or alterationwithout defeating its practicability, and I therefore do not wish to beconfined to the preferred embodiment shown in the drawings and describedherein, further than I am limited by the scope of the appended claims.

I claim:

l. In an electrical hearing aid for one ear of a human being, thecombination with a body of non-conductive material formed to t and beretained within the wearers ear cavity and including a source ofelectric energy, of: an outwardly presented transmitter carried by saidbody; a receiver presented inwardly toward the inner ear of the wearersear cavity and carried by the wearers body; and a germanium transistordisposed within said body and interconnected with said source ofelectric energy, transmitter, and receiver, whereby sonic signals pickedup by the transmitter are amplified by the germanium transistor andreproduced through the receiver.

2. In an electrical hearing aid for one ear of a human being, thecombination with a body of non-conductive material formed tocontiguously nest within the concha and the hollow of the fossa ofanthelix of the wearers ear and be retained therein, said body having astudportion extending into the external auditory canal and a laterallyextending portion which is nested by the hollow of the fossa of anthelxof the wearers ear, and a source of electric energy carried by saidlaterally extending portion; of: an outwardly presented transmitterrigidly carried by said body within the concha of the wearers ear;

an inwardly presented receiver rigidly carried by the innermost end ofsaid stud-portion; and at least one germanium transistor disposed withinsaid body and operatively interconnected with said source of electricenergy, transmitter, and receiver, whereby sonic signals picked up bythe transmitter are amplified by the germanium transistor and reproducedthrough the receiver.

3. In a hearing aid for one ear of a human being, the combination with abody of non-conductive material formed to tit within and be retained byan ear cavity, of: the wearers outwardly presented transmitter carriedby said body; a receiver presented inwardly toward the inner ear of thewearer and carried by said body; a germanium transistor disposed withinsaid body; and a bimetal thermogenerator externally carried by that partof said body in contact with the ear cavity of the wearer andinterconnected with said transmitter, said receiver and said germaniumtransistor, whereby bodyheat from the ear generates a thermoelectriccurrent which operates the transmitter, germanium transistor, andreceiver for amplifying sonic signals.

4. In a hearing aid for one ear of a human being, the combination with abody of non-conductive material formed to contiguously nest within theconcha and the hollow of the anthelix of the users ear and be retainedtherein, and having a stud-portion extending into the external auditorycanal, of: an outwardly presented transmitter rigidly carried by saidbody within the concha of the users ear; an inwardly presented receiverrigidly carried by the innermost end of said stud-portion; a germaniumtransistor disposed within said body; and a bimetal thermogeneratorexternally carried by that part of said body in contact with the usersear and interconnecting said transmitter, said receiver, and saidgermanium transistor, whereby body heat from the ear generates athermoelectric current which operates the transmitter, germaniumtransistor, and receiver for amplifying sonic signals.

References Cited in the tile of this patent UNITED STATES PATENTS

